Protein involved in G protein-coupled receptor mediated signal transduction with ability to mediate signal transduction from a dopamine D1 receptor or an adenosine A2A receptor to an adenylate cyclase and utilization thereof

Abstract

A novel protein (Gm1) includes an amino acid sequence part having a high homology with a domain having a high homology with a GTP binding site and a GTPase site conserved among G protein α subunits and a trimer forming domain conserved among G protein α subunits. The Gm1 protein is involved in signal transduction via a G protein-coupled receptor (GPCR) stimulation. The Gm1 protein is expressed intensively in human brain, thymus, testes, spleen, small intestine, uterus and heart. A method for screening for a substance capable of regulating a cellular signal transduction employs a polynucleotide encoding the Gm1 protein.

1. An isolated protein comprising any amino acid sequence selected from the group consisting of:
 (a) the amino acid sequence represented by SEQ ID NO:1; 
 (b) an amino acid sequence of a protein involved in a G protein-coupled receptor mediated signal transduction, wherein the protein has an ability to mediate a signal transduction from a dopamine D1 receptor or an adenosine A2a receptor to an adenylate cyclase, and wherein the amino acid sequence has a homology of 85% or more with the amino acid sequence represented by SEQ ID NO:1 and retains the amino acid sequences represented by amino acid Nos. 119 to 133, 287 to 292, 353 to 359 and 428 to 435 in the amino acid sequence of SEQ ID NO:1; 
 (c) the amino acid sequence represented by SEQ ID NO:25; and 
 (d) the amino acid sequence represented by SEQ ID NO:26. 
 
     
     
       2. An agent for regulating a G protein-coupled receptor mediated signal transduction containing as an active ingredient a protein according to  claim 1 . 
     
     
       3. An isolated protein
 consisting of the amino acid sequence represented by SEQ ID NO:1. 
 
     
     
       4. An isolated protein consisting of the amino acid sequence represented by SEQ ID NO:25. 
     
     
       5. An isolated protein consisting of the amino acid sequence represented by SEQ ID NO:26.